Problems in cars rarely ever cure themselves. This being said, give it a shot and try to resolder the module. It is fairky simple.
If it works and you can return the new unit, you saved yourself a few hard earned kronors.

I thought the P80 V70 3rd brakelight was LED. What else coulb be that tiny and bright with only 3W (if I remember the value on the V70 bulb indicator assembly correctly)?

I'd start by pulling the instrument cluster and disassembling it. Maybe this reveals something.

it kinda amazes me there are no solutions out there to fix a problematic OBD reading. Wait, VW found something, maybe they are willing to share their knowledge ...

Hang in there! It might be just an easy thing. New cars mean lots of dollars or new problems.

The big 302 mm brakes will not clear the 15 inch rims. But they are rare. If you have them, buy new smaller discs and sell the adapter brackets. That should get you rolling.

Interestingly, my 94 T5 wagon is very comfy with its 16 inch wheels. Maybe that is because the shocks and springs are well worn in and my reference 96R with the 17 inch wheels and Volvo sport suspension is really harsh. But, try to play with the tire pressure. Don't go too low of course, that is dan...

Not sure if you do it frequently, but getting these bricks airborne breaks the motor mounts. Just saying ...

Would it help if I tried this with my M4.3 T5M?
Just wondering because you should have ME7 and ETM and coilpacks.

yes. there should be instructions in the manual.
i'm not bear the car so I can't look it up